1. Technical Field
The present disclosure relates to a vehicle front body structure for vehicles, such as automobiles, and particularly to the vehicle front body structure that reduces damages to a power unit when an obstacle collides diagonally from front.
2. Related Art
Typical vehicle front body structures of automobiles have a pair of left and right front side frames projected forward in the vehicle from a toe board that is a bulkhead of a cabin front part. The left and right front side frames serves as a base to which sub-frames and cross members to which, for example, front suspensions are attached, and to which, for example, various exterior parts are attached. An engine room is formed in a gap between the left and right front side frames, and a power unit including an engine and a transmission are mounted therein.
For such a vehicle front body structure, an improvement of anti-collision performance is demanded by controlling various deformation at the time of a collision. For example, Japanese Unexamined Patent Application Publication (JP-A) No. 2012-214211 discloses a control of a deformation mode of a vehicle body by using branch frames that are branched outwardly in vehicle width directions from the respective front side frames, and fragile parts provided rearward of the respective branch frames, etc., in order to improve a performance against a front collision outside either one of the front side frames (a narrow offset collision), Further, JP-A No. 2009-012703 discloses a stiffener, of which a front end edge having a step is disposed so as to bridge over an assumed break line in front-and-rear directions, is lap-welded to each front side frame, in order to control a break mode of the front side frames at the time of an offset collision.
These days, it becomes problematic that, when an obstacle collides diagonally from front of a vehicle, strong parts such as bumper beams and tie-down hooks are pushed relatively rearward into a vehicle body main part due to axial collapse of the front side frames, resulting in damages to a power unit such as an engine. The vehicle front body structure is required that does not cause serious damages to the power unit even at the time of such a diagonal collision.